1. Field of the Invention
The present invention relates to an absorbent article including a composite sheet obtained by affixing two types of sheets having different ratios of expansion and contraction.
2. Related Art
Conventionally, disposable diapers, for example, have been known as absorbent articles. The disposable diapers widely employed for babies and children to the elderly persons and physically-handicapped persons have been replaced with reusable absorbent articles made of cloth. Such a disposable diaper generally includes an absorbing member in an elongated shape arranged along a longitudinal direction and a chassis having a leg-surrounding portion recessed inward in a width direction on both sides in the width direction formed therein, and composed of a composite sheet obtained by affixing two sheets. According to Japanese Unexamined Patent Application, First Publication No. 2004-136068 (hereinafter referred to as “patent publication 1”), some composite sheets have been manufactured by a method of coating the whole surface of one of the two sheets with adhesives, finely arranging a thread-shaped stretchable member between the two sheets, and bonding the other sheet thereto.
Additionally, as disclosed in Japanese Unexamined Patent Application, First Publication No. 2002-143218 (hereinafter referred to as “patent publication 2”), there is also a technique for affixing a sheet-shaped stretchable sheet to a non-stretchable sheet to manufacture a composite sheet in order to enhance the appearance and the fitting properties of a diaper in the shape of pants. FIG. 6 is a front view of a diaper in the shape of pants 201 using a composite sheet 213 obtained by affixing such stretchable and non-stretchable sheets 215 and 216, respectively, to each other for portions including a trunk-surrounding portion and a leg-surrounding portion of the diaper. The composite sheet 213 is formed of two sheets, i.e., the non-stretchable sheet 216 on the side of a skin contacting surface directed toward the body of a wearer and the stretchable sheet 215 on the side of a non-skin contacting surface that is the opposite side of the skin contacting surface and affixed to each other with adhesives applied to the entire surfaces of the sheets.
When the non-stretchable sheet 216 and the stretchable sheet 215 are thus affixed to each other with the adhesives applied to the entire surfaces of the sheets, a warping portion 225 that warps toward the non-skin contacting surface, i.e., a portion having a height no less than two times that of the other portions in a stationary state or a portion with a front surface appearing to be turned toward the reverse surface or reverse surface appearing to be turned toward the front surface in a stationary state occurs at a cut edge 204 of a leg-surrounding portion 203a. FIG. 7 is an enlarged view of the region A of FIG. 6, showing a cross-sectional view of a portion where such a warping portion 225 occurs. The arrows show an expansion and contraction direction (ECD) at the portion. The non-stretchable sheet 216 on the side of the skin contacting surface is pulled with a contractive force of the stretchable sheet 215 on the side of the non-skin contacting surface so that the warping portion 225 occurs. When the warping portion 225 is thus provided in the chassis 203, adhesion between the skin and the composite sheet 213 is degraded, so that a gap occurs between the skin and the composite sheet 213. Therefore, urine is likely to leak out of the gap.
An objective of the present invention is to provide an absorbent article that does not easily warp in a leg-surrounding portion.
The inventors of the present invention have performed thorough examination in order to attain the above-mentioned objective. As a result, they have found that when a stretchable sheet and a non-stretchable sheet are bonded to each other, and adhesive portions are provided to extend in a direction substantially perpendicular to an expansion and contraction direction between the sheets at a cut edge of both the sheets to prevent a warping portion from occurring at the cut edge, the present invention is achieved. Specifically, an objective is to provide the absorbent article described below.